System for discharging stacked granular material



Sept. 1, 1959 E. BUHRER 2,902,189

SYSTEM FOR DISCHARGING JSTACKED GRANULAR MATERIAL Filed July 22, 1957 4Sheets-Sheet l IN V EN TOR.

Sept. 1, 1959 E. BUHRER 2,902,139

SYSTEM FOR DISCHARGING STACKED GRANULAR MATERIAL Filed July 22, 1957 4Sheets-Sheet 2 Fig. 3

IN V EN TOR.

Ekh i/v $11M ER Sept. 1, 1959 E. BUHRER 2,902,189

SYSTEM FOR DISCHARGING STACKED GRANULAR MATERIAL Filed July 22, 1957 4Sheets-Sheet 3 Fig.6

I QVVENTOR. ERh/ 1 N Bu/MER Sept. 1, 1959' E. BUHRER 2,902,189

SYSTEM FOR DISCHARGING STACKED GRANULAR MATERIAL Filed July 22, 1957 4Sheets-Sheet 4 INKENTOR.

- ERHi/v mum United States Patent SYSTEM FOR DISCHARGING STACKEDGRANULAR MATERIAL Erwin Biihrer, Schafihausen, Switzerland ApplicationJuly 22, 1957, Serial No. 673,345

Claims priority, application Switzerland July 27, 1956 9 Claims. (Cl.222-199) The present invention relates to method and means fordischarging granular material, in particular, but not exclusively foruse in foundry molds.

It is known to strew granular material upon a surface by passing thisgranular material through a sieve. -Such known process has, however, thedisadvantage that the amount of granular material strewed onto thesurface varies to a great extent and within wide limits, may dififerwith respect to quantity of the material at various areas. Moreover thedeposit of the sieved out granular material along marginal surfaceportions cannot be obtained with sufficient accuracy. A furtherdisadvantage is that only relatively small quantities of material pertime unit may be deposited onto a surface by this known method.

It has also been proposed to fill pulverized glass from a container intomolds by using as the bottom of the container a grid structure and byoscillating this grid structure by means of electromagnetic means.

Moreover, it is known to provide a silo with a gratelike bottom and tomove rods of a movable grate member between the rods of a stationarygrate member. This movement may either be a horizontal reciprocatorymovement or a combined vertical and horizontal reciprocatory movement,so that the granular material loosened up by this movement may passthrough the spaces between the rods of the stationary grate member in aregulatable manner. It is further known to strew granular material bysubjecting a non-resilient and substantially rigid grid supporting saidgranular material, to a vibratory movement.

If granular material is to be dispensed in large quantities per timeunit from a silo the above described methods and means may not be useddue to the fact that either the spacing between the rods of theoscillating grate member would have to be so large, that in position ofrest such grate member would be unable to safely support and maintainthe granular material above said grate.

Alternatively, if a smaller spacing between these rods were chosen theamount of granular material to be discharged Would be reduced in a noncontrollable and uneven manner due to the precompaction of this granularmaterial above the grate. Such precompaction of the granular materialabove the discharge grate is, however, always undesirable.

It is, therefore, an object of the present invention to provide meansenabling discharge of granular material from a storage or like spacethrough even distribution and in a relatively loose state and manner.

A further object of the present invention is to provide a novel systemof delivering a relatively large quantity of granular material per timeunit in a controlled manner of distribution.

Still a further object of the present invention is the provision ofmeans rendering the possibility of supporting granular material withinthe storage space in stationary condition and to discharge such granularmaterial thereafter at will, so that the material assumes a condition ofmovement, by gravity and at a predetermined state which does not requireany after-treatment.

Another object of the present invention is to provide means fordischarging granular material from a storage space and for preventingprecompaction to a considerable extent of said material prior to orduring such discharge movement.

A further object of the present invention is to provide meansfacilitating support of said granular material in one position,preferably in a position of rest, and imparting to said material acutting action while said granular material is being released fordischarge from said support to contribute certain characteristics andproperties to said granular material, which are desirable in foundrymold production and for other purposes, such as in the plastic industry,powder metallurgy and ceramic technique employing granular materials.

Another object of the present invention is the provision of meanspermitting a plurality of grate rods or members in a position of rest tosupport granular material thereabove, while same assumes an archorbridgeshaped configuration; whereas in an operative position in whichsaid grate rods or members perform non-uniform oscillatory motionsrelative to each other and in a vertical direction said bridge-shapedconfiguration will be subjected to constant changes, thereby deprivingsaid granular material while bringing the latter into a loose state, ofits support and consequently causing same to be discharged between saidgrate rods.

Still a further object of the present invention is the provision ofmeans conducive to the structure of a grate assembly at the lower end ofa storage receptacle or silo, as well as at a location adjacent to saidlower end, which grate assembly permits safe storage and retainment ofsaid granular material during a condition of rest and discharge of saidmaterial in predetermined quantity and texture for subsequent use.

It is still another object of the present invention to provide meansforming a plurality of grate members arranged for oscillatory up anddownward movements relative to each other, and to provide further meansto effect said up and downward movements of said grate members atpredetermined displacement of phase.

A further object of the present invention is the pro vision ofoscillation generating means for controlilng the movements of said gratemembers to be carried out in a relationship of displacement of phase.

Another object of the present invention is the provision of a dischargedevice adapted to deliver molding sand from a storage receptacledirectly into a mold box and above pattern means arranged therein in amanner so as to bring about uniform and even loose state of said sandaround said pattern means and throughout said mold.

Further objects and advantages will become apparent from the followingdetailed description, reference being made to the accompanying drawings,showing a preferred embodiment of the invention.

In the drawings:

Fig. l is a section taken along line I-l of Fig. 3, showing materialdischarge means embodying the present invention to facilitate strewingof granular material in a loose manner.

Fig. 2 is a section taken along lines 11-11 of Fig. 1.

Fig. 3 is a side elevation of Fig. 1, as seen in the direetion of arrowA.

Fig. 4 is an elevational fragmentary view of a part shown in Fig. 5, asseen in the direction of arrow B.

Fig. 5 is an elevational fragmentary view of said part of Fig. 4, asseen in the direction of arrow C.

Fig. 6 is a elevational view, as seen in the direction 3. of arrow D inFig. 7, a partial section being taken along line VIVI of Fig. 7.

Fig. 7 is an elevational view, partly in section, as seen in :the.direction of arrow. E in Fig; 6, thev section being, taken along'lines-VJtlVlI of Fig. 6..

Fig; 8 is arnel'evationalview, asseen irrthedi-rection oflarrowfF-of-Fig;.;.9, parts being; shown .in section, taken along; lines.V-HI.-VHI of. Big. 9;

Fig; 9 isan.-elevational view, asseen' in thedirection. of arrow G ofFig. 8, a section being takenralonglines IX 1IX- of Pig. 8;

Fig;. isa: modification. of the. material discharge means .of Figs. 1to-3.; shown schematically and invertie-a1 section.

Figs .,lOa-l0c ELEQTESRECilVfi schematic representations of=threedifferent relative-positions of the grate-rods employableinthe:modification shown-in-Fig 10.

Referring now-more particu-larly to the attached. drawings-, .thererisdisclosed. in Figs. 1 to 3' a device'or equip ment which comprisesaframe. 2 supported by;- standards: l-tfromiazsupportSlI'llCill16',(I10t shown). Frame 2 forms eat-chamber 3= whichisfilledout bylead. On-theframe 2-;axsiloo5Tis supported bymeans ofbrackets 4, WhiClIsSilO- contains granular; material'd. InadditiontheframeZ: carries an; electric motor 7,.whichis operativelyconnected :With shafts 8:. and.;9 :via couplings ltt and Y 11;,respec-tively-.. ShaftzS is'rotated by motor 7.:andfdrivesvia atpairaofbevel: gears. 12, .a:shaft' 13; .whereas; shaft .9:im-.' parts rotation:through apair 'ofz-bevel gear-5.1410 :a ishafti 15;. An upper:grate4men1berxi6 issuspended.sfromzfour: connectingrods .17, which :are;journaled' iniexcenter beareings it? of shafts 13 andzlSg-respectively;Alowergrate. memberrl is suspendedfrom .connectingi .rodsZtl; whicharejournaled .on shafts. 13uand'15, respectively, .in .excenten bearings.zlithereof. Rods 22 mournedon' the framezZ: carry. biased springs 23:andl, .which- .resilientlytsupportt the upper: grate member 16 at.theirrinternal flanges-127: and'which' in turn abut-against shoulders 25and 26, .re.- spectively. Respective pairs of springs 29.and.3t}.abut:-against shoulders 26 and 23, respectively,andisupportthe lowergrate/"member l9 onflanges-31thereof.. The upper gratermember Itddsprovided with carrier bars or: rods 32,-.which together with thecorresponding-gratemembei framesupportgrate rods 33. The lowergrate.member: 19 comprises carrier bars-or rods 34 supporting grate rods-35.

The/carrier bars-32; onthe one hand, are provided withtrecesses 36=which permit in-upwarddirection acertainamount of play'of the grate.rods 35, which are rigidly connected to the carrierbars 34.Thecarrienbars or-rods 34, on the other hand; are providedwith recesses317, which-permit a corresponding amount-of play, in downward direction,to thegrate. rods 33; which are rigidlyconnected with the carrier barsor-rods32.

In Fig. 1 the two grate "members-are shown to be in theposition o-frest,i.e.- in a medianposition withrespect to their amplitude of vibration orreciprocation. Aswill-be seen from this Fig. l the upper edges'of thegrate rods 33 and 35 are positioned approximately on the same level-inthis median position. While it has been found that this arrangement ofthe grate rods is mostsuitable, it will be understood that a verticaldisplacement of the upper edges in the median position of the gratemembers lfi and 19 is also possible. The characteristicsof the springsv23:, 24-, 29, and.30;are.suitably chosen so.that.the springs may takeup the acceleeration forcesoftthegrate. members 16 and.19, respectively,when unloaded orrin idle condition.

The device just described operates in accordance with Figs. 1 to 3asnfollows in order-to supply granular material:

Whenthe electric motor 7 is put into operation, this motor rotatesshaft8 in the direction of arrow 39-via couplinglti and'pair of bevelgears 12, so that shaft 13 is rotated in the directionof arrow 33.Shaft'9'wil1 simultaneously be rotated via coupling 11 in the directionof arrow 40, and this rotation is imparted to shaft 15 via pair of bevelgears 14 in the. direction of arrow 41.

Due to the rotation of shafts 13 and 15 the eccentric bearings 18 and 21effect an upward and downward movement of the grate members 16 and 19via the connecting rods 17 and 20, respectively. Since the eccentricbearings 18are displaced with respectto thezeccentric bearings 21 'by anangleofi 'the'upward and downward movements or reciprocations of theupper grate member 16-are effectuated witha'displacementof phase of 180?'withvrespect to the upward and downward :movements of reciprocations ofthe lower grate member 19.

The silo 5rcontaining= granular material in servesto'provide means formaintainingaminimunrheight of deposit or supply of material required foran even delivery of granular material throughout the whole area of thegrate members.

When themotor'7 is nottintoperation the gratecrods 33? member-19.:wil-lcarry out a downward movement... When? the; two grate-members; have:reached 1 the: respective: ex treme positions;of;their1reciprocations,theirrdirections. of movement are;reversed.

Therefore; the.,grate member 16- will thenxperfornr a; downward and:the: grate member 19: an :upward. move-.- ment. It will bennderstoodthatupon .initiationof llhfifferi ciprocating movement of thegrate members the. granular i'rrateria'lswillrrest only,v onthengratetrodss33 whilerafter; thezreversal. of: the. directionoftmovement the: granular material. will besnpported: only. by thegrate. rodseSSE This :iSsdilGi .-to:the. rfactzthat .the' grate:.rods33. r andsSS; 're; spectively,'.during theitdownward: movement will septaratez; themselvesfromi theazgranularz material:

Due; to: the; above; described manner, a condition is. reached; which?in; operationncorresponds substantially.- to twicethe; actualdistance-rhetween-itwo"adjacent 1 grate; rods; furthermore,certainr.pointsi.of, thev granular material are alternatively subjectedto pressure and to: a: reduced amount also to tension, .i.e.': asimulated 'cutting orrlooseninguaetioniis-utransmitted to the: granularmaterial.v

Due to. this measure a: bridge formation b'etween adja cent gratemembers is completely avoided and thereby: a1l ENIlla11d-6fi6CtiV6=discharge ofgranular material (lureings operation ofi the device isensured.

Tests which :were -carriecl'out with molding:- sand ='l1'ave shown thatthis arrangement of grate members is capablev of r depositing an amountof sand per time 1' unit- 1 which is several times greater than-theamount which may= bedepositedwith conventional devices I operatingatequal reciprocation frequencies and amplitudes:

Moreover, the aforesaid arrangement of the present in vention permits toreduce'to a traction undesirable-com-;- paction of the granular materialabove-the grate rods" as comparedwith conventional devices.-

1n: an alternative arrangementof the apparatus arrange-- ment shownin-"Figsa 1 to 3 it .is possible-to actuate th'e grate rods overindividual "eccentric" bearings and to connect tthese rods 'so' that inoperation the behavior of the grate. composed of 1 these -:grate rodswill correspond'to' 'a grate the grate rods' of which arespaced' fromeach =other= by three or four times the actual distance"betweenadja centgrate-rods;

The'amplitude of reciprocation 'ofthe individual grate rods ispreferablyychosenso that'only each third; fourth; etc. grate rod'supports'the material." As means for feed ing' granular material'it ispossible to arrange below a.

silo a turning plate or turntable having a wiper member. In order tocontrol the height of granular material supported above the grate, anelectric feeler member may be arranged which determines the operation ofthe turning plate.

Figs. 4 and 5 show a modified form of a rectangular silo 42 while Figs.6 and 7 show a modified form of an upper grate member 43 adapted foroperation with silo 42 of Figs. 4 and 5. In Figs. 8 and 9 a modifiedform of a lower grate member 44 is shown.

Tests made in connection with the discharge of granular material inloose state have shown that, if the dimensions of the apparatus foreffecting such discharge exceed in length and width certain measurementsand if the crosssections are rectangular, as is normally the case, itwill be seen that in operation of the apparatus the granular material isin a less loose state in the central portions above the grate membersthan along the marginal portions thereof. In the corner areas of thegrate members the granular material may be in such loose state that theentire granular material will fall through during operation. Themodifications shown in Figs. 4 to 9 illustrate means which permit thedischarge of even amounts of granular material over large rectangularcross-sections with a minimum and even precompaction of this granularmaterial.

Figs. 4 and 5 show that the lower edge portions of silo 42 lie in ahorizontal plane only at points 45 and along edges 46, whereas theremaining edge portions 47 and 48v are inclined towards marginal or endedges 49 defining the corners of the silo. In order to prevent a flow ofgranular material from silo 42 to the upper grate member 43 cooperatingtherewith, the upper silo 42 is provided at its corners with upwardlyextending wall portions.

Due to the fact that the lower corner portions of silo 42 are cut off,the effect of increased friction is substantially compensated for, thisfriction normally being larger in the corner portions of the silo thanin the central portion thereof. However, with the lower corner portionsof the silo being cut away the friction in these corners is reduced toan amount which is substantially equal to the friction encountered inthe central portions of the silo. The friction caused by the aforesaidelevated wall portions of the upper grate member is substantiallycompensated for by their reciprocation in operation of the apparatus.

It will be noted that spacing 53 between adjacent grate rods 54 of theupper grate member 43 and spacing 51 between grate rods 52 of the lowergrate member 44 are larger than the spacings 56 and 55 betweencorresponding grate rods, spacings 53 and 51 being employed in thecentral portions of the grate members, whereas spacings 56 and 55 areapplied to the marginal portions of said grate members. Due to thismeasure a further equalization of the depositing or dischargingconditions over the full area of the grate is effected.

A further measure serving this end may be found in the configuration ofthe carrier rods 57 and 58, respectively. In order to further equalizethe discharge of the granular material, the central carrier rods 57 ofthe grate member 43 are of greater height as indicated by edge 59, i.e.they extend deeper into the granular material than the carrier rods 58,the upper edges of which are indicated at 60.

Moreover, the height of these carrier rods is reduced adjacent themarginal portions of the respective grate member, as indicated at 61 and62, respectively, i.e. these edge portions 61 and 62 are located on asubstantially lower level than the edge portions 59 and 60,respectively.

It has been common practice to reciprocate the grates for dispensing ordepositing granular material by means of electromagnets. However,investigations and tests have shown that the reciprocation amplitude ofthe grate is directly responsible for the amount of granular material tobe discharged. If the characteristics of the granular material or theheight of the granular material stored above the grates change duringoperation, this change will,- in grates driven by electromagnets, resultin a variation of the reciprocation amplitude and therefore in avariation of the amount of granular material discharged per time unit.On the other hand, it is possible to maintain the amount of dischargesubstantially constant despite such changes, if the grates arereciprocated by means which ensure a constant reciprocation amplitude,such as eccentric rod means shown in Figs. 1 to 3.

If the discharge of granular material is to be efiected intermittentlyand if the number of operating phases per time unit is very high, it isadvisable to alrange between the drive motor and the shaft carrying theeccentric bearings, operable couplings or clutches which periodicallyengage said shaft while the drive motor operates continuously.

Referring now further to a modified embodiment schematically illustratedin Fig. 10 discharge means employing the grate members for handlinggranular material are shown. 70 indicates the lower end of a storage binor silo for granular material, mounted in a manner similar to that ofthe silo of Fig. 1. Three grate members 72, 73, and 74 are arranged insuperposed relation below silo 70 and supported on springs 75, 76; 77,78, and 79, 80, respectively by means of bolts 71. It will be understoodthat bolts 71 corresponds to bolts 21, shown in Fig. 1.

The grate member 72 comprises a plurality of horizontally extendingparallel grate rods 81 arranged on intermediate carrier means and inspaced relation to each other. Similarly grate member 73 comprises graterods 82, while grate member 74 is provided with grate rods 83. It willbe noted from Fig. 10 that the arrangement or sequence of the individualgrate rods is such that they form a substantially continuous row inwhich a grate rod 82 follows a grate rod 83 and a grate rod 81 follows agrate rod 82, so that these grate rods are positioned in predeterminedsequence over the whole length of said row.

If silo 70 is filled with granular material 84 this granular materialwill be supported in the position of rest by the grate rods 81, 82, 83of the grate members 72 to 74. This due to the tendency of the granularmaterial of assuming arch-shaped or bridge-shaped formations over theaforesaid support forming grate rods which within a certain maximumdistance between two grate rods will prevent the granular material fromsinking and flowing downwardly out of the silo 79.

Means not shown, but comparable to rods 17 and 20, eccentric bearings 18and 21, shafts 13 and 15 and drive motor 7 seen in Figs. 1 to 3, areprovided to impart to each of the grate members 72 to 74 an individualreciprocating up and downward movement. To this end, each one of thethree grate members will be operatively connected to four eccentricbearings over four connecting rods, the eccentric bearings connected toone grate member being angularly displaced With respect to a secondgrate member and the latter being angularly displaced with respect tothe eccentric bearings of the third grate member, so that upon operationof a drive motor the individual grate members and consequently theirgrate rods will reciprocate with a displacement of phase.

Whereas this displacement of phase is suitably chosen to be 180 in thecase of two grate members working together as in the embodiment of Figs.1 to 3, this displacement of phase is 120 according to the modificationshown in Fig. 10.

Figs. 10a to depict the relative positions of the grate rods in threedifferent phases of movement of the grate members. In Fig. 10a the graterods 83 are shown to assume an upper extreme position, whilesimultaneously grate rods 82 and 81 are in respective lower extremepositions. Fig. 10b shows grate rods 82 in an upper extreme position,whereas .grate rods '81 and '83 take up a lower extreme position. Fig. cindicates grate rods 81 in an upper extreme positionand grate rods '82and 83 .in a lower extreme position.

Due to the operation-of the grate member assembly, as described inconnection with -Figs. 10a to 10 the elfect of the grate rods upon thegranular material is comparable to an arrangement in which the distancebetween adjacentgrate rods is three-times greatenthau the distanceshown'in Fig. 10. Consequentlyythe granular material supported bythegrate rods in a position of'rest of the aforesaid assembly or device isnot only brought into a looser'statethan-by-means of 'the device ofFigs. 1 to 3 having only two individuallyreciprocating grate members,but also'a greater quantity-of granular material may thus be dischargedfrom silo 70. :In addtion this device according to Fig. 10 permits todischarge in a more loose state the granules of said material havingpossibly a strong tendency to bind or :st-icl -together, due to thedifferentiated reciprocating motions of the three grate'members, i.e. ofthe grate rods thereof.

From the above it will be understood that devices may be constructed inaccordancewith --the present invention having four or'rnoreindividuallyreciprocating grate members, the grate rodsof'which'forminga composite grate. Furthermore, the-numberofgrate-members to be employed may be chosen in accordance with theproperties of the granular material; a granulanmaterial of low bindingtendency necessitating a smaller and a material of highbindingtendencynecessitatinga greater number of individuallyreciprocating grate members.

The theory which is fundamental for the-system and device of discharginggranularmaterial according to'the present invention and in a mannerdescribed hereintofore will now be explained in greater detail. -It maybe assumed that the granular material is supported above the grate rodsof very narrow width due 'to its "tendency of producingarch-shapedorbridge-like configurations at the lowermost end. At a givendistance a predetermined type of granular material will dueto'thistendency become self-supporting over-the grate rods and,therefore, discharge of the material through the grate members in theirpredetermined position of rest is prevented. An increase in distancebetween adjacent grate rods will reduce the firmness of support of-thegranular material above these grate rods, i.e. the possibility ofdischarge increases with increasing distance between said grate rods.

At a critical distance between adjacent gratero'ds a small increasetherein may bring about a destruction .or collapse of the arch orbridge'formation'in the mass of granular material and therewith anunintentional discharge of the granular material in a position of restofthe grate rods.

The critical distance between adjacent grate rods-in a position of restis, however, largely afunction or the condition and composition of thegranules of material. In loose state a predetermined type of granularmaterial will have a lesser tendency of assuming an arch formation thanin a precompacted state. This factor is to a certain extent adverse tothe discharge of granular material, since the reciprocation of'the graterods will bring about a precompaction of the granular material when incontact therewith. As a consequence'thereof, the amount of granularmaterial will, theretore,'becon siderably reduced due to thisprecompaction.

border to discharge granular material'in a controlled manner, itbecomes, therefore, necessary to change the condition of support of thestacked granular material which gives rise to the aforesaid arch.or'bridge'formation between the position of rest, i.e. when thematerial is stored, and the position of movement, i.e. when the materialis to be discharged.

To this end, the present invention'makes use of a grate assembly inwhich adj acent-graterods carry 'out different reciprocating motions,whereby the distance between the points or lines of support of thegranular material is increased in said position of motion with-respecttosaid position of rest. In accordance with the number of grate unitsormembers employed the increase indistance may be two, three or fourtimes the initial distance due'to the fact that with an assembly havingtwo grate-members-only each second, with an assembly having three gratemembers only each third, etc. grate rod carries out equal movements and,therefore, will-support the granular material. It is, therefore,understood, that while the granular material may safely be supportedabove the grate members in said position of rest, discharge of granularmaterial in a very loose state beinginsured'during-operation or movementof. the grate members, even'if the'granules of the material-may have astrong tendency of binding together, undesirable discharge of thematerial during said position of rest being absolutely avoided.

Various changes and modifications may bemade without departing from thespirit and scope of the present invention and it isintended that suchobvious changes and modifications be embraeed'by the annexed claims.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent, is:

1. A system for discharging granular material from'a storage receptacle,comprising at-least two grate members arranged in superposed relationbelow said storage receptacle, said grate members being arranged toeffectuate from a position of rest upwardand downward -movementsindependently ofeach other and having 'each-aplurality of horizontallyextending grate rods, said graterods of said grate members formingtogether in said position of rest a substantially horizontal row inpredetermined relative vertical positions of said grate-members, saidgrate rods connected to the one of said grate members alternating withsaid grate rods connected to the other of said grate members in saidrow, adjacent grate rods in said row being spaced in a horizontal planefrom each other a distance sufficient to prevent'said granular materialin said'storage receptacle from being discharged'therefrom in saidposition of rest, thereby substantially supporting said granularmaterial in-said storage receptacle, reciprocation generating meansoperatively connected with each of said grate members, saidreciprocation 'generating means being adapted to eifect saidupward anddownward movements of'said grate members'into and out ofsaid position ofrest and being arranged with respect toeach other to efiect adisplacement .of 1 phase in said movements, drive means connected tosaid reciprocation generating means for actuating same, said upward anddownward movements of said grate members bringing about a looseningaction of adjacent .ones of said grate rods upon said granular material,whereby said granular material will be evenly discharged from saidstorage. space through said grate members and between said grate rodsthereof overlarge cross-sectional areas.

2. A system for discharging stacked granular material normally stored ina silo and like space; comprising a plurality of successively arrangedand superpositioned grate means disposed for phase-controlledreciprocating motion in upand downward directions relative to eachother, a plurality of grate rod meansmounted on each.of said grate meansand spaced from each other a predetermined distance, means forcontrolling and varying the phase of reciprocating motion of said gratemeans, and means for maintaining in .a position of rest said grate meanswith said rod meansito support said stacked material for imparting saidreciprocating motion to said. grate means, respectively, inpredetermined phasedisplacement relation during said motion of said ro'dmeans, to discharge stacked material'in asubstantiallyloose state fromsaid silo space into a receptacle.

3. A system according to claim 2, the reciprocating motion of one ofsaid grate means having a displacement of phase of 180 with respect tothe oscillatory motion of another of said grate means.

4. A system according to claim 2, the distance of said grate rod meansfrom each other of one of said grate means differing from the distanceof the grate rod means of the other of said grate means.

5. A system for discharging stacked granular material normally stored ina silo and like space; comprising a plurality of successively arrangedand superpositioned grate means disposed for phase-controlledreciprocating motion in upand downward directions relative to eachother, a plurality of grate rod means mounted on each of said gratemeans and spaced from each other a predetermined distance, means forcontrolling and varying the phase of reciprocating motion of said gratemeans, and means for maintaining in a position of rest said grate meanswith said rod means to support stacked material and for imparting saidreciprocating motion to said grate means, respectively, in predeterminedphase displacement relation during said motion of said rod means, todischarge stacked material in a substantially loose state from said silospace into a receptacle, the distance of said grate means rod means fromeach other of one of said grate means diifen'ng from the distance of thegrate rod means of the other of said grate means, the distance betweensaid grate rod means from each other being greater adjacent the centerof one of said grate means than the distance between said grate rodmeans remote from said center of said one grate means, and wherein thedistance between said grate rod means adjacent the center of another ofsaid grate rod means is greater than the distance between the grate rodmeans of another of said grate means, the distance between said graterod means adjacent the center of said one grate means diifering from thedistance of said grate rod means adjacent the center of said other gratemeans.

6. A system for discharging stacked granular material normally stored ina silo and like space; comprising a plurality of successively arrangedand superpositioned grate means disposed for phase-controlledreciprocating motion in upand downward directions relative to eachother, a plurality of grate rod means mounted on each of said gratemeans and spaced from each other a predetermined distance, means forcontrolling and varying the phase of reciprocating motion of said gratemeans, and means for maintaining in a position of rest said grate meanswith said rod means to support stacked material and for imparting saidreciprocating motion to said grate means, respectively, in predeterminedphase displacement relation during said motion of said rod means, todischarge stacked material in a substantially loose state from said silospace into a receptacle, the distance between the grate rod means of oneof said grate means dilfering from the distance between the grate rodmeans of another of said grate means and the distance between the graterod means of a further grate means being larger than the distancebetween the respective grate rod means of said one grate means and ofsaid other grate means.

7. A system for discharging stacked granular material normally stored ina silo and like space; comprising a plurality of successively arrangedand superpositioned grate means disposed for phase-controlledreciprocating motion in upand downward directions relative to eachother, a plurality of grate rod means mounted on each of said gratemeans and spaced from each other a predetermined distance, means forcontrolling and varying the phase of reciprocating motion of said gratemeans, and means for maintaining in a position of rest said grate meanswith said rod means to support stacked material and for imparting saidreciprocating motion to said grate means, respectively, in predeterminedphase displacement relation during said motion of said rod means, todischarge stacked material in a substantially loose state from said silospace into a receptacle, wherein said grate rod means of the uppermostof said grate means being of greater height adjacent the center of saiduppermost grate means than the height of the grate rod means remote fromsaid center of said uppermost grate means.

8. A system for discharging stacked granular material normally stored ina silo and like space; comprising a plurality of successively arrangedand superpositioned grate means disposed for phase-controlledreciprocating motion in up-and downward directions relative to eachother, a plurality of grate rod means mounted on each of said gratemeans and spaced from each other a predetermined distance, means forcontrolling and varying the phase of reciprocating motion of said gratemeans, and means for maintaining in a position of rest said grate meanswith said rod means to support stacked material and for imparting saidreciprocating motion to said grate means, respectively, in predeterminedphase displacement relation during said motion of said rod means, todischarge stacked material in a substantially loose state from said silospace into a receptacle, the space of said silo and the uppermost gratemeans being defined by respective walls, the walls of said silo and thewalls of said uppermost grate means providing substantially polygonalformations, respectively, the walls of said silo at the lowermost end ofthe latter being shaped so that the height of said walls thereof isshorter at the corners of said silo than at the remaining wall portionsthereof, the walls of said uppermost grate means being greater in heightat edges of said uppermost grate means located adjacent said corners ofsaid lowermost end of said silo.

9. A system for discharging granular material from a storage space;comprising a plurality of grate means forming the bottom of said storagespace and extending in spaced horizontal relation to each other, saidgrate means being arranged for movement in upward and downwarddirections, at least one of said grate means being arranged for upwardand downward movement independently of an adjacent one of said gratemeans, a plurality of reciprocation generating means, one of saidreciprocation generating means being connected to at least one of saidgrate means, another of said reciprocation generating means beingconnected to at least another of said grate means arranged adjacent saidone grate means, and drive means connected to said reciprocationgenerating means to operate the latter whereby in a position of rest ofsaid grate means said granular material will be supported above thelatter, whereas upon operation of said reciprocation generating meanssaid granular material will flow downwardly within the confines of saidgrate means, said reciprocation generating means being adapted to impartto said grate means upward and downward movements in a phasedisplacement relation to each other, to thereby bring said material intoa loose state and to increase and provide a substantially uniformdownward flow of said granular material from said storage space.

References Cited in the file of this patent UNITED STATES PATENTS

